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United States Patent |
6,260,938
|
Ohtsuka
,   et al.
|
July 17, 2001
|
Ink-jet printing method and apparatus for printing with inks of different
densities
Abstract
It is checked whether an ink used in a printhead has a high density. The
type of a printing medium used for a print operation is also identified.
An image is printed by scanning the printhead once or a plurality of
times. When a print operation is to be performed by using a thick ink, an
image is printed by using mask data and the driving frequency of the head
which are set for the thick ink. When a print operation is to be performed
by using a thin ink, an image is printed by using mask data and the
driving frequency of the head which are set for the thin ink and the type
of printing medium used for the print operation. Codes of the respective
color data of print data are determined in accordance with the types of
inks used for a print operation, and an image is printed by printing a
plurality of dots or dots in an overlapping state by the multi-pass
method.
Inventors:
|
Ohtsuka; Naoji (Yokohama, JP);
Yano; Kentaro (Yokohama, JP);
Takahashi; Kiichiro (Kawasaki, JP);
Nishikori; Hitoshi (Inagi, JP);
Iwasaki; Osamu (Tokyo, JP);
Kanematsu; Daigoro (Yokohama, JP);
Kanda; Hidehiko (Kawasaki, JP)
|
Assignee:
|
Canon Kabushiki Kaisha (Tokyo, JP)
|
Appl. No.:
|
847740 |
Filed:
|
April 22, 1997 |
Foreign Application Priority Data
| Apr 23, 1996[JP] | 8-101711 |
| Apr 23, 1996[JP] | 8-101712 |
Current U.S. Class: |
347/15; 347/14; 347/19 |
Intern'l Class: |
B41J 002/205 |
Field of Search: |
347/14,15,19,43,12,40,41
358/298
|
References Cited
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| |
Primary Examiner: Barlow; John
Assistant Examiner: Hallacher; Craig A.
Attorney, Agent or Firm: Fitzpatrick, Cella, Harper & Scinto
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is related to U.S. patent applications Ser. Nos.
08/844,854, 08/847,743, 08/847,744 and 08/847,984, all filed on Apr. 22,
1997.
Claims
What is claimed is:
1. An ink jet printing apparatus for printing an image on a printing medium
by using an ink, comprising:
a mount portion on which replaceable first and second ink-jet printheads
can be mounted, said first ink-jet printhead discharging a first ink
having a relatively high density, and said second ink-jet printhead
discharging a second ink having a color similar to the first ink and a
density lower than the density of the first ink; and
print control means for performing a print operation controlled by at least
one of an upper limit of the amount of ink ejected per unit area and an
amount of ink ejected per unit time, in accordance with the density of the
first or second ink in said printhead mounted on said mount portion and a
type of printing medium, wherein the print operation is performed using
the first ink or the second ink, and when the second ink is used, the
second ink is discharged in an overlapping manner on the printing medium.
2. The apparatus according to claim 1, further comprising discrimination
means for discriminating the density of the ink used by said printhead,
and
wherein said print control means changes mask data for masking print data
in accordance with a discrimination result obtained by said discrimination
means.
3. The apparatus according to claim 2, wherein said print control means
changes a driving frequency of said ink-jet printhead in accordance with
the discrimination result obtained by said discrimination means.
4. The apparatus according to claim 2, wherein said printhead performs the
print operation while moving relatively to the printing medium, and
said print control means changes the number of times of scanning required
for said printhead to print data corresponding to one scanning operation
in accordance with the discrimination result obtained by said
discrimination means.
5. The apparatus according to claim 2, wherein said print control means
changes the mask data on the basis of a type of printing medium when said
discrimination means discriminates that the ink in said printhead mounted
on said mount portion is ink having relatively low density.
6. The apparatus according to claim 2, wherein said print control means
changes a driving frequency of said printhead on the basis of a type of
printing medium when said discrimination means discriminates that the ink
in said printhead mounted on said mount portion is ink having relatively
low density.
7. The apparatus according to claim 2, wherein said printhead performs the
print operation while moving relatively to the printing medium, and
said print control means changes the number of times of scanning required
for said printhead to print data corresponding to one scanning operation
on the basis of the type of printing medium when said discrimination means
discriminates that the ink in said printhead mounted on said mount portion
is ink having relatively low density.
8. The apparatus according to claim 1, further comprising discrimination
means for discriminating the density of the ink used by said printhead,
and identification means for identifying the type of the printing medium,
wherein said print control means changes mask data for masking print data
in accordance with a discrimination result obtained by said discrimination
means and an identification result obtained by said identification means.
9. The apparatus according to claim 8, wherein said print control means
changes a driving frequency of said ink-jet printhead in accordance with
the discrimination result obtained by said discrimination means and the
identification result obtained by said identification means.
10. The apparatus according to claim 8, wherein said printhead performs the
print operation while moving relatively to the printing medium, and
said print control means changes the number of times of scanning required
for said printhead to print data corresponding to one scanning operation
in accordance with the discrimination result obtained by said
discrimination means and the identification result obtained by said
identification means.
11. The apparatus according to claim 1, further comprising detection means
for detecting information about an environment in which said apparatus is
installed,
wherein said print control means changes mask data in accordance with a
detection result obtained by said detection means.
12. The apparatus according to claim 1, further comprising detection means
for detecting information about an environment in which said apparatus is
installed,
wherein said print control means changes a driving frequency of said
ink-jet printhead in accordance with a detection result obtained by said
detection means.
13. The apparatus according to claim 1, wherein said printhead performs the
print operation while moving relatively to the printing medium, and
said print control means further comprises detection means for detecting
information about an environment in which said apparatus is installed, and
changes the number of times of scanning required for said printhead to
print data corresponding to one scanning operation on the basis of a
detection result obtained by said detection means.
14. The apparatus according to claim 1, wherein each of said ink-jet
printheads is an ink-jet printhead for discharging ink by using heat
energy, said printhead having a heat energy converter for applying heat
energy to the ink.
15. An ink-jet printing method of printing an image by discharging an ink
from a printhead mounted on a mount portion onto a printing medium,
comprising:
the step of determining whether a first ink-jet printhead discharging a
first ink having a relatively high density or a second ink-jet printhead
discharging a second ink having a color similar to the first ink and a
density lower than the density of the first ink is mounted; and
the print step of performing a print operation controlled by at least one
of an upper limit of the amount of ink ejected per unit area and an amount
of ink ejected per unit time, in accordance with the density of the first
or second ink in the printhead mounted on the mount portion and a type of
printing medium, wherein the print operation is performed using the first
ink or the second ink, and when the second ink is used, the second ink is
discharged in an overlapping manner on the printing medium.
16. The method according to claim 15, further comprising the step of
identifying the type of printing medium,
wherein the print step comprises performing the print operation while
controlling at least one of the upper limit of the amount of ink ejected
from said printhead per unit area of the printing medium and the upper
limit of the amount of ink ejected from said printhead onto the printing
medium per unit time on the basis of the information about the determined
density of the ink in said printhead and the information about the
identified type of printing medium.
17. The method according to claim 15, wherein the print step comprises
changing mask data for masking image data used for the print operation on
the basis of a discrimination result obtained in the step of determining
the mounted printhead.
18. The method according to claim 15, wherein the print step comprises
changing mask data for masking image data used for the print operation on
the basis of a discrimination result obtained in the step of determining
the mounted printhead and the type of printing medium.
19. The method according to claim 15, wherein the print step comprises
changing a driving frequency of said ink-jet printhead in accordance with
density of the ink.
20. The method according to claim 15, wherein the print step comprises
changing a driving frequency of said ink-jet printhead in accordance with
the type of printing medium.
21. The method according to claim 15, wherein said printhead performs the
print operation while moving relatively to the printing medium, and the
print step comprises changing the number of times of scanning required for
said printhead to print data corresponding to one scanning operation in
accordance with density of the ink.
22. The method according to claim 15, wherein said printhead performs the
print operation while moving relatively to the printing medium, and the
print step comprises changing the number of times of scanning required for
said printhead to print data corresponding to one scanning operation in
accordance with the type of printing medium.
23. The method according to claim 15, wherein the print step comprises
changing the mask data in accordance with the type of printing medium if
it is discriminated in the determining step that the second ink-jet
printhead is mounted.
24. The method according to claim 15, wherein the print step comprises
changing a driving frequency of said printhead in accordance with the type
of printing medium if it is discriminated in the determining step that the
second ink-jet printhead is mounted.
25. The method according to claim 14, wherein said printhead performs the
print operation while moving relatively to the printing medium, and the
print step comprises changing the number of times of scanning required for
said printhead to print data corresponding to one scanning operation if it
is discriminated in the determining step that the second ink-jet printhead
is mounted.
26. The method according to claim 15, further comprising the detection step
of detecting information about an environment in which said printhead is
installed,
wherein the print step comprises changing mask data in accordance with a
detection result obtained in the detection step.
27. The method according to claim 15, further comprising the detection step
of detecting information about an environment in which said printhead is
installed,
wherein the print step comprises changing a driving frequency of said
printhead in accordance with a detection result obtained in the detection
step.
28. The method according to claim 15, further comprising the detection step
of detecting information about an environment in which said printhead is
installed,
wherein the print step comprises changing the number of times of scanning
in accordance with a detection result obtained in the detection step.
Description
BACKGROUND OF THE INVENTION
The present invention relate to an ink-jet printing method and apparatus
for printing an image on a printing medium by discharging an ink from a
printhead onto the medium, and a printing system including the printing
apparatus.
A printer apparatus such as a printer, a copying machine, or a facsimile
machine is designed to print an image consisting of dot patterns on a
printing medium such as a paper sheet or a thin plastic film on the basis
of image information. The print schemes for such printer apparatuses can
be classified into an ink-jet scheme, a wire dot scheme, a thermal scheme,
a laser beam scheme, and the like. Of these schemes, the ink-jet scheme
(ink-jet printer apparatus) is designed to discharge/spray an ink
(printing material) from the orifices of the printhead and cause the ink
to adhere to a printing medium, thereby printing an image.
With the widespread use of printer apparatuses, demands have recently
arisen for printer apparatus which can realize high-speed print
operations, high resolution, high image quality, low noise, and the like.
As a printer apparatus which can meet such demands, an ink-jet printer
apparatus is available. The ink-jet printer apparatus is designed to print
an image by discharging an ink from the printhead, and hence can perform a
non-contact print operation. This printer apparatus can therefore obtain a
very stable image.
With the recent developments in various types of digital cameras, digital
videos, CD-ROMs, and the like, pictorial image data can be easily
processed on applications in host computers. Consequently, printer
apparatuses as output devices are required to have a function of
outputting pictorial images. Conventionally, such pictorial image output
operations are performed by high-end silver salt type printer apparatuses
designed to print images upon reception of digital image data and
expensive sublimation type printer apparatuses whose application is
limited to photographic outputs using sublimable dyes.
In the above prior art, a printer apparatus exclusively used for prints of
photographic images and the like is very expensive. This is because such a
printer apparatus uses the silver salt scheme which requires a complicated
process, and is too large to be used as a desktop type apparatus. Consider
a printer apparatus designed to use sublimable dyes. As is known, in this
case as well, as the size of a printing medium increases, the
manufacturing cost of the main body and the running cost considerably
increase. That is, such printer apparatuses cannot be easily used in
homes. The most critical drawback of these printer apparatuses is that
they are designed to use special printing media. That is, the applications
of the printer apparatus are limited. For this reason, it is totally
impossible for one printer apparatus to allow the user to selectively
perform print operations using various types of printing media as in home
and business use, e.g., printing images based on data from a wordprocessor
or graphic data using plain paper in the normal mode and printing
photographic images and the like using special printing media in the
pictorial print mode.
According to improved printer apparatuses, especially ink-jet printer
apparatuses, in order to solve these problems, image processing, coloring
materials, printing media, and the like have been improved. Recently,
therefore, great improvements have been made in the image quality of
photographic images printed by ink-jet printer apparatuses.
In addition, as is known, a printer apparatus is becoming popular, which
serves both as a monochrome printer apparatus and a color printer
apparatus upon replacement of an ink cartridge integrally constituted by a
printhead and an ink tank. Such a printer apparatus has been developed to
enhance the monochrome print function of printing out images based on data
from a wordprocessor at a high speed, and realize a function of printing
color graphic images by using the limited resources of one printer
apparatus. Most users are demanding this technique. This printer apparatus
has a function of recognizing the type of ink cartridge and optimizing a
print operation by, e.g., switching control for a monochrome cartridge and
control for a color cartridge. At present, replacement of an ink cartridge
is performed to only exchange a color ink and a monochrome ink.
Various studies have been made to improve the gradation characteristics of
color graphic outputs in color print operations. For example, the
resolution for such a print operation is set to be higher than that in the
color print mode to improve the printing performance. The resolution of a
printer apparatus is increased, and multivalued data is sent as print data
to the printer apparatus. The printer apparatus then performs a
multivalued output operation using sub-pixels. Such improvements have been
proposed and put into practice.
In addition, a method of printing an image on a printing medium by using
coloring materials having different pigment densities at once has been
proposed to allow an ink-jet printer apparatus to print out a pictorial
image. A printer apparatus designed to print an image by preparing two
types of coloring materials having different pigment densities for each of
coloring materials of C, M, Y, and K or C, M, and Y, and using them at
once, unlike a general printer apparatus which uses four or three coloring
materials of C, M, Y, and K or C, M, and Y, has been proposed. According
to this printing scheme, the color reproduction range can be greatly
broadened, and the graininess of an image can be made greatly reduced by
printing a high-lightness area (in which printed dots are discretely
present on a printing medium) of the image by using a coloring material
having a low pigment density. In contrast to this, a low-lightness,
high-saturation area is printed by using a coloring material having a high
pigment density, which reduces the graininess of the resultant image,
thereby obtaining an image with good color development.
In the above method, however, many types of coloring materials must be
contained in one printer apparatus. The printer apparatus therefore
becomes a very complicated system. In general, users print monochrome
images in most cases. For this reason, it is often useless to always have
coloring materials having low pigment densities in the printer apparatus
at the same time. Furthermore, since the size of the printhead is limited,
the maximum capacity for a print operation or the capacity of an ink tank
for each coloring material must be reduced, thus posing problems.
The pigment density of a coloring material such as an ink is determined by
the maximum necessary density in the system to be designed. The pigment
density is determined to obtain a necessary optical reflection density
from the maximum ejection amount in the system. In general, if the maximum
saturation of a primary color (CMYK) is obtained by an ink injection
amount of 100%, almost the maximum saturation of a secondary color (RGB),
which is the sum of primary colors at 100%, can also be obtained. In order
to broaden the color reproduction range, therefore, the pigment density of
a coloring material must be increased to further increase the density of
the coloring material so as to obtain the maximum saturation of a primary
color with an ink ejection amount of 100%. For this reason, the graininess
of a pictorial image becomes conspicuous. That is, this method is not
suited for business use of graphic images.
According to another method, the maximum ejection amounts of primary and
secondary color inks can be set to 200% and 400%, respectively, by
decreasing the pigment densities. In a general ink-jet printer apparatus,
however, since the maximum amount of coloring material which can be
received is determined by the type of printing medium, the types of
printing media which can be used are limited. For this reason, the
versatility of the ink-jet printer apparatus deteriorates, and the running
cost is high.
As described above, when a print operation is to be performed by using a
thin ink, a relatively large amount of ink must be ejected onto a printing
medium. In practice, the graininess of dots of thick ink, e.g., black,
cyan, or blue inks, can be effectively and greatly reduced by setting the
density of such an ink to about 1/3 or less that of a conventional ink.
According to a simple calculation, in this case, in order to obtain an
image having almost the same color density as that of an image printed by
using a conventional thick ink, the thin ink must be ejected onto a
printing medium in an amount about three times that of the conventional
ink.
In general, if the amount of ink injected onto a printing medium per unit
time exceeds the ink receiving capacity of the printing medium, or the
amount (ink ejecting rate) of ink ejected onto a printing medium per unit
time exceeds the ink absorbing rate of the printing medium, the ejected
ink overflows the printing medium, resulting in a blurred image.
Alternatively, the ink moves on the printing medium because of the surface
tension. As a result, the printed image has high- and low-density
portions, and hence the image quality deteriorates.
When a print operation is to be performed by using a thin ink, in
particular, a large amount of ink must be ejected onto a printing medium
to increase the density of an image. The above problem therefore tends to
arise.
In order to meet the needs of the users, the print speed of the printer
apparatus must be increased beyond a predetermined speed. For this
purpose, the moving speed of the carriage or the driving speed of the head
must be increased. Accordingly, the ink ejecting rate increases. As a
result, problems such as an ink overflow arise more easily.
SUMMARY OF THE INVENTION
The present invention has been made in consideration of the above
conventional techniques, and has as its object to provide an ink-jet
printing system which allows one printer apparatus to exchange and use
cartridges or ink tanks containing inks having different color properties,
and can print a high-quality image by exchanging these cartridges or ink
tanks, and an ink-jet printing method and apparatus.
It is another object of the present invention to provide an ink-jet
printing system which can print a high-quality photographic image with the
gradation level being increased and the graininess being greatly reduced
by printing it using inks having different color properties, and an
ink-jet printing method and apparatus.
It is still another object of the present invention to provide an ink-jet
printing system which can print an image upon changing the amounts of
coloring materials ejected in accordance with the saturation and density
of each ink used for a print operation such that the densities of pigments
ejected onto a printing medium become almost the same, and setting optimal
ink ejection amounts in accordance with the type of printing medium, and
an ink-jet printing method and apparatus.
It is still another object of the present invention to provide an ink-jet
printing system in which when a print operation is performed by using a
thin ink, an image having almost the same density as that of an image
obtained by using a thick ink can be efficiently obtained, and an ink-jet
printing method and apparatus.
It is still another object of the present invention to provide an ink-jet
printing system which can print a high-quality image while suppressing a
decrease in print speed and preventing an ink from overflowing, and an
ink-jet printing method and apparatus.
It is still another object of the present invention to provide an ink-jet
printing system which can obtain a high-quality image by changing at least
the print data, the print cycle, or the number of times of scanning in
accordance with at least the saturation of an ink used for a print
operation, the density of the ink, or the type of printing medium, and an
ink-jet printing method and apparatus.
It is still another object of the present invention to provide an ink-jet
printing system which performs a print operation using a thin ink by
changing at least the number of times of scanning or the driving frequency
of the head in accordance with the type of printing medium, thereby
preventing the ink from overflowing the printing medium without decreasing
the print speed, and an ink-jet printing method and apparatus.
Other features and advantages of the present invention will be apparent
from the following description taken in conjunction with the accompanying
drawings, in which like reference characters designate the same or similar
parts throughout the figures thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated in and constitute a part
of the specification, illustrate embodiments of the invention and,
together with the descriptions, serve to explain the principle of the
invention.
FIG. 1 is a block diagram showing the overall arrangement of a printing
system including a host computer and a printer apparatus according to an
embodiment of the present invention;
FIG. 2 is a perspective view showing the arrangement of the mechanical
portion of the ink-jet printer apparatus of the embodiment from which the
front cover is removed;
FIG. 3A is a perspective view showing the head cartridge and ink tanks of
the ink-jet printer apparatus of the embodiment, and FIG. 3B is an
enlargement thereof;
FIGS. 4A and 4B are perspective views showing the mechanical arrangement of
the printhead of the ink-jet printer apparatus of the embodiment;
FIG. 5 is a view showing a circuit arrangement for discriminating the type
of ink in the printhead in the embodiment;
FIG. 6A is a view showing the contact portion of the head cartridge in the
ink-jet printer apparatus of the embodiment, and FIG. 6B is an enlargement
thereof;
FIG. 7A is a view for explaining the arrangement of the printhead in a case
wherein an ink tank is detachably mounted in the printhead, and FIG. 7B is
an enlargement thereof;
FIG. 8 is a flow chart showing the processing performed by a color
processing module in a printer driver in the embodiment;
FIG. 9 is a view for explaining the relationship between the pigment
density of an ink, data, a printing medium, and the maximum ejection
amount in the embodiment;
FIG. 10 is a graph for explaining the relationship between the dye
(pigment) density of an ink and the reflection density in the embodiment;
FIGS. 11A and 11B are views showing the layout of dots printed on a
printing medium in the ink-jet printer apparatus of the embodiment, in
which FIG. 11A shows the dots printed at 360 dpi, and FIG. 11B shows the
positions of the dots printed on the basis of multivalued data;
FIGS. 12A to 12C are views showing print data and the layouts of print data
in the embodiment, in which FIG. 12A shows a case of binary data, FIG. 12B
shows a case of quaternary data, and FIG. 12C shows a case of quinary
data;
FIG. 13 is a block diagram showing the arrangement of an ink-jet printer
apparatus according to the first embodiment of the present invention;
FIG. 14 is a flow chart showing the print code generation processing
performed by the printer driver of the host computer in the first
embodiment;
FIG. 15 is a flow chart showing the print processing in the ink-jet printer
apparatus of the first embodiment;
FIG. 16 is a flow chart showing the print processing based on the
multi-pass method in the ink-jet printer apparatus of the first
embodiment;
FIG. 17 is a view showing how data are exchanged between the host computer
and the printer apparatus in the first embodiment;
FIG. 18 is a flow chart showing the print mode setting processing in the
second embodiment of the present invention;
FIGS. 19 to 21 are views showing samples displayed on the screen when a
print mode is manually set in the second embodiment;
FIG. 22 is a flow chart showing an example of the image processing
performed by an image processing module in the printer driver in the
second embodiment;
FIG. 23 is a perspective view showing printhead cartridges containing
different types of inks and the printer apparatus main body according to
the second embodiment;
FIG. 24 is a block diagram showing the arrangement of a printer apparatus
of the second embodiment;
FIG. 25 is a graph showing the relationship between the identification code
of a head cartridge and the ink ejection amount;
FIGS. 26A and 26B are views showing examples of mask data in the third
embodiment of the present invention;
FIGS. 27A and 27B are views showing other examples of the mask data in the
third embodiment;
FIG. 28 is a block diagram showing the arrangement of an ink-jet printer of
the apparatus of the third embodiment of the present invention;
FIG. 29 is a flow chart for explaining print control performed by the
ink-jet printer apparatus of the third embodiment of the present
invention;
FIG. 30 is a flow chart showing print processing in step S135 in FIG. 29;
FIG. 31 is a flow chart for explaining print control performed by an
ink-jet printer apparatus according to the fourth embodiment of the
present invention; and
FIG. 32 is a flow chart for explaining print control performed by an
ink-jet printer apparatus according to the fifth embodiment of the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The characteristic features of an embodiment of the present invention will
be described below prior to the description of the preferred embodiments.
(1) In the embodiment, a printer apparatus main body discriminates whether
a printhead including a cartridge containing a relatively thick ink or a
printhead including an ink cartridge containing at least a thin ink of one
color is mounted. When a print operation is to be performed using a thin
ink, the operation is performed by a divisional printing method (to be
described later) of discharging the ink by the same number of times as in
a print operation using a thick ink. In this case, when a print operation
is to be performed using a thin ink, the amount of ink discharged per
scanning operation is larger than that in a print operation using a thick
ink. In addition, the driving frequency of the printhead is set, and the
maximum amount of ink ejected per unit time is determined so as to prevent
the ink from overflowing the printing medium (print paper or the like)
selected by the user. This operation prevents the ink from overflowing the
printing medium, and allows a print operation at the maximum speed while
forming a high-quality image with little graininess.
(2) At least the amount of ink ejected or the maximum amount of ink ejected
is changed in accordance with a combination of pigment densities upon
identification of the ID data of an ink cartridge or setting of ID data.
The embodiment includes a means of changing at least the amount of
coloring material discharged onto a printing medium or the maximum amount
of coloring material discharged.
(3) According to an improved form of the embodiment, when coloring
materials having relatively low pigment densities are used, a color is
separated into primary and secondary color components for each pixel, and
the maximum amount of coloring material ejected is determined for each
nth-order color component instead of simply increasing the maximum amount
of coloring material ejected in accordance with the ratio between the
pigment densities. A characteristic feature of this form is that, in this
determination step, the amount of coloring material of each nth-order
color component is independently regulated and increased to its maximum
amount instead of being simply increased. With this operation, even if
coloring materials having relatively low pigment densities are used, both
images of primary and secondary color components have almost the same
optical reflection densities as those obtained by using coloring materials
having relatively high pigment densities. In addition, an increase in the
amount of ink ejected can be suppressed, and hence an increase in running
cost can be suppressed.
(4) In output data from a color processing module typified by a printer
driver or the like, conversion of print data of each color into binary
data or conversion into multivalued data can be selectively performed in
accordance with the pigment density of a coloring material used for a
print operation. In addition, the embodiment has a function of outputting
multivalued data or high-resolution data when a mode requiring better
gradation characteristics is set.
The preferred embodiments of the present invention will be described in
detail below with reference to the accompanying drawings.
FIG. 1 is a block diagram for explaining the functional arrangement of a
printing system including a host computer 100 and a printer apparatus
(ink-jet printer) 200 according to the embodiment of the present
invention.
Referring to FIG. 1, in the host computer 100, the exchange of various data
and control are generally performed between an OS (Operating System) 101
and application software 102 which operates on the OS 101. Print data is
exchanged between the OS 101, the application software 102, and a printer
driver 103, and is sent to the printer apparatus 200 through the printer
driver 103.
The flow of data in the process of printing out a color image from the
printer apparatus 200 by using the application software 102 for handling
pictorial images will be described below.
If the image data generated/edited by the application software 102 is
pictorial image data, the data is sent as multivalued R, G, and B signals
to the printer driver 103. The printer driver 103 performs color
processing for the received multivalued R, G, and B signals, and also
performs halftone processing for the signals to generally convert them
into binary C (cyan), M (magenta), Y (yellow), and K (black) signals. The
printer driver 103 then sends these signals to the interface, in the host
computer 100, which is used for the printer apparatus 200 or the interface
for a file storage unit or the like.
In this embodiment, the signals are output to the interface for the printer
apparatus 200, and the data are sent to controller software 201 in the
printer apparatus 200. Matching and the like between the set print mode
and a head cartridge 203 are checked. Thereafter, the print data is
transferred to engine software 202. In this case, the engine software 202
interprets the received data as data indicating the print mode and the
data structure designated by the controller software 201, converts the
print data into discharge pulses, and sends them to the head cartridge
(printhead) 203. With this operation, coloring materials (inks) are
discharged from the head cartridge 203. The ID information of the head
cartridge 203, the ID information of each ink tank, and the like are sent
to the engine software 202. On the basis of these pieces of information
about the head cartridge 203, the engine software 202 assigns print
buffers for storing print data of the respective colors, and optimizes
various settings. The pieces of information are further sent to the host
computer 100 and used as pieces of information for, for example, decoding
data sent from the printer driver 103 by referring to the print mode and
the like.
FIG. 2 shows the mechanical arrangement of the printer apparatus 200 using
replaceable cartridges according to the preferred embodiment of the
present invention, and more specifically, the ink-jet printer apparatus
from which the front cover is removed to allow the interior of the printer
apparatus to be seen.
Referring to FIG. 2, reference numeral 1 denotes a replaceable head
cartridge (corresponding to the head cartridge 203 in FIG. 1) having an
ink tank portion which contains an ink and a printhead; 2, a carriage unit
which has the head cartridge 1 mounted thereon and moves laterally to
perform a print operation; and 3, a holder for fixing the head cartridge 1
to the carriage unit 2. The holder 3 is interlocked with a cartridge
fixing lever 4. That is, when the cartridge fixing lever 4 is operated
after the head cartridge 1 is mounted in the carriage unit 2, the head
cartridge 1 is pressed against the carriage unit 2. With this operation,
positioning of the head cartridge 1 and electrical contact between the
head cartridge 1 and the carriage unit 2 can be ensured. Reference numeral
5 denotes a flexible cable for transferring an electrical signal to the
carriage unit 2; 6, a carriage motor which rotates to reciprocate the
carriage unit 2 in the main scanning direction; 7, a carriage belt which
is driven by the carriage motor 6 to move the carriage unit 2 laterally;
8, a guide shaft for slidably holding the carriage unit 2; 9, a home
position sensor having a photocoupler which is used to position the
carriage unit 2 to its home position; and 10, a light-shielding plate
which allows detection of the home position. When the carriage unit 2
reaches the home position, the light-shielding plate 10 blocks the light
from the photocoupler mounted on the carriage unit 2. As a result, it is
detected that the carriage unit 2 has reached the home position. Reference
numeral 12 denotes a home position unit including, for example, a
restoring mechanism for a printhead 1 of the head cartridge 1; and 13, a
paper discharge roller for discharging a printing medium. The printing
medium is sandwiched between the paper discharge roller 13 and a spur unit
(not shown) and discharged outside the printer apparatus. Reference
numeral 14 denotes an LF unit for conveying the printing medium in the
sub-scanning direction by a predetermined amount.
FIG. 3 shows the detailed structure of the head cartridge 1 used in the
embodiment of the present invention.
Referring to FIG. 3, reference numeral 15 denotes a replaceable black (Bk)
ink tank; 16, a replaceable ink tank containing C, M, and Y coloring
materials; 17, coupling ports (coloring material supply ports) of the ink
tank 16, which are coupled to the head cartridge 1 to supply the coloring
materials; and 18, a coupling port (coloring material supply port) of the
ink tank 15. The coupling ports 17 and 18 are designed to be coupled to
supply pipes 20 to supply the coloring materials. Reference numeral 19
denotes a contact portion for electrical signals, which is connected to
the flexible cable 5 to transfer various signals to the head cartridge 1.
FIGS. 4A and 4B show the structure of the printhead 1 according to the
embodiment. FIG. 4A is a perspective view showing the outer appearance of
the printhead 1 when viewed from the rear side. FIG. 4B is a perspective
view showing the printhead 1 when viewed from the front side.
Orifice groups corresponding to the respective colors, i.e.,. yellow,
magenta, cyan, and black, are arranged in a line on the front surface
portion of the printhead 1. Each of the orifice groups for yellow,
magenta, and cyan consists of 24 orifices (nozzles). The orifice group for
black consists of 64 orifices (nozzles). The nozzle groups for the
respective colors are arranged at a pitch of one nozzle or more.
The printhead 1 has ink channels communicating with the respective
orifices. A common liquid chamber is formed behind the ink channels to
supply inks thereto. Electrothermal converters for generating heat energy
used to discharge the inks from these orifices, and an electrode wiring
pattern for supplying power thereto are arranged in the ink channels
corresponding to the respective orifices. These electrothermal converters
(discharge heaters) and the electrode wiring pattern are formed on a board
2001 consisting of silicon or the like by a film forming technique.
Partition walls, a ceiling plate, and the like consisting of resin and
glass materials are stacked on the board 2001 to form the above orifices,
the ink channels, and the common liquid chamber. A driving circuit for
driving the electrothermal converters in accordance with print signals is
mounted in the form of a printed board behind the board 2001.
Instead of using the above glass material or the like, a grooved ceiling
plate (orifice plate) having partition walls, a common liquid chamber, and
the like formed thereon to define the respective ink flow paths may be
bonded to the board 2001. In this case, the grooved ceiling plate is
formed by integral molding. As a molding material, polysulfone is
preferably used. However, other molding resin materials may be used.
The board 2001 and a printed board 2002 are mounted parallel to an aluminum
plate 2003 having the same shape as that of the printed board 2002. Pipes
2004 to 2007 extend from a plastic member 2008 called a distributor
extending in a direction perpendicular to the board 2001, and communicate
with the channels in the plastic member 2008. The channels communicate
with the common liquid chamber. There are four channels for yellow,
magenta, cyan, and black in the plastic member 2008. The channels
communicate with the common liquid chamber for the inks of the respective
colors and the pipes 2004 to 2007.
In the embodiment, the ink tanks for the color inks and the black (Bk) ink
are independently prepared and independently replaceable. However, the
head cartridge obtained by integrating the ink tanks 15 and 16 and the
printhead 1 may be used.
About 40 ng of an ink are discharged from each of the orifices for yellow,
magenta, and cyan arranged in the printhead 1 in the embodiment, whereas
about 80 ng of an ink are discharged from the orifice for black (Bk).
The following are examples of the compositions of the inks used in the
ink-jet printer apparatus of the embodiment:
1. Y (yellow):
Direct Yellow CI 86 3 parts by weight
diethylene glycol 10 parts by weight
isopropyl alcohol 2 parts by weight
urea 5 parts by weight
Acetylenol EH, (Kawaken Chemical) 1 part by weight
water balance
2. M (magenta):
Acid Red CI 289 3 parts by weight
diethylene glycol 10 parts by weight
isopropyl alcohol 2 parts by weight
urea 5 parts by weight
Acetylenol EH (Kawaken Chemical) 1 part by weight
water balance
3. C (cyan):
Direct Blue CI 199 3 parts by weight
diethylene glycol 10 parts by weight
isopropyl alcohol 2 parts by weight
urea 5 parts by weight
Acetylenol EH (Kawaken Chemical) 1 part by weight
water balance
4. Bk (black):
Direct Black CI 154 3 parts by weight
diethylene glycol 10 parts by weight
isopropyl alcohol 2 parts by weight
urea 5 parts by weight
water balance
As described above, unlike the black (Bk) ink, 1% of Acetylenol EH is added
to each of the C, M, and Y inks to improve its permeability. As an
additive, a surfactant, alcohol, or the like other than the above compound
is available.
In the embodiment, the printhead 1 is made to hold information indicating
whether it contains a thick ink having a high density or a thin ink having
a low density. The ink-jet printer apparatus main body identifies the
information.
FIG. 5 is a wiring diagram for explaining a means of identifying the ink
information of the printhead 1 according to the embodiment.
The wiring pattern shown in FIG. 5 is formed in the head cartridge 1. Any
one of points A, B, and C in FIG. 5 is disconnected in accordance with the
type of ink contained in the printhead 1.
In the ink-jet printer apparatus main body, a voltage is applied between
terminals 1 and 4 of this circuit to identify the type of ink in the
printhead 1 depending on whether the terminal 1 and a terminal 2 are
disconnected from each other (high density), the terminal 1 and a terminal
3 are disconnected from each other (low density), or the terminal 1 and
the terminal 4 are disconnected from each other (normal) in the wiring
pattern in FIG. 5 which is formed in the printhead 1.
The contact portion 19 has a plurality of pads. Signals associated with ink
discharging operations, an ID signal for identifying the head cartridge 1,
and the like are exchanged between the head cartridge 1 and the ink-jet
printer apparatus main body through the pads of the contact portion 19.
Another method of detecting the type of ink tank in the head cartridge 1
used in the embodiment will be described below.
FIG. 7 is a view for explaining the method of detecting the type of ink
tank in the head cartridge 1 used in the embodiment.
When the ink tank 15 (or 16) is mounted in the head cartridge 1, and a hook
70 is engaged with a projection 73 of the tank, the ink tank 15 is fixed
on the head cartridge 1. Contact portions 71 for detecting the type of ink
tank mounted are formed in the direction in which the force of the hook 70
acts. The tank detecting contact portions 71 are formed on both the head
cartridge 1 side and the ink tank 15 (or 16) side. Referring to FIG. 7,
reference numeral 72 indicates an enlarged view of the contact portion 71,
which has three pads 1, 2, and 3. Although not shown, similar pads equal
in number to the above pads are formed on the head cartridge 1 side. These
pads are electrically connected to each other on the contact portions 71.
Assume that on the contact portion on the ink tank 15 (or 16) side, the
pads 1 and 2 are set conductive, but the pad 3 is insulated. Assume that
this state indicates an ink tank containing a normal ink. In this case,
the ink-jet printer apparatus of the embodiment is electrically connected
to these pads through the contact portion on the head cartridge 1 side
which is in contact with the pads to detect the type of ink contained in
the ink tank mounted in the printer apparatus main body.
In the case shown in FIG. 7, a current flows between the pads 1 and 2, but
no current flows between the pads 1 and 3 and between the pads 2 and 3.
Information indicating this state is stored in advance in a ROM or the
like in the ink-jet printer apparatus main body as information indicating
that a normal ink tank is mounted. In contrast to this, on an ink tank
containing a thin ink, for example, the pad 3 is set conductive to allow
the printer apparatus to identify the ink tank different from the normal
ink tank.
In the embodiment, the number of pads for identifying an ink tank is three.
If, however, four or more pads are used, more types of ink tanks can be
identified.
In addition, whether the head cartridge 1 is replaced can be detected by
checking the conductive state through the contact portion 19 shown in
FIGS. 5 and 6.
[First Embodiment]
FIG. 8 is a flow chart showing an example of image processing performed by
an image processing module in a printer driver 103 according to the first
embodiment of the present invention.
In step S101, luminance/density conversion is performed to convert R, G,
and B luminance signals, i.e., 8-bit R, G, and B signals, i.e., input
signals consisting of a total of 24 bits, into C, M, and Y signals, i.e.,
8-bit C, M, and Y signals, i.e., signals consisting of a total of 24 bits,
or C, M, Y, and K density signals consisting of a total of 32 bits. In
step S102, masking is performed to correct unnecessary color components of
the pigments in the C, M, and Y coloring materials. In step S103, UCR/BGR
processing is performed to remove undercolors and extract black
components. In step S104, for each pixel, primary and secondary color
coloring materials are limited to different ejection amounts. In this
case, the primary and secondary color coloring materials are limited to
300% and 400%, respectively.
In step S105, output gamma correction is performed to make the output
characteristics linear. Up to this processing, the 8-bit multivalued
outputs of the respective colors are used. In step S106, halftone
processing is performed for the 8-bit signals to convert the C, M, Y, and
K data into 1- or 2-bit signals. In this case, in step S106, halftone
processing is performed by using the error diffusion method, the dither
method, or the like.
FIG. 9 shows the classification of the contents of control selectively
executed by the control unit of the printer apparatus on the basis of the
head identification signal or the ink tank identification signal (ID
signal) from a contact portion 19 of the head cartridge 1.
In the first embodiment, the four types of cartridges are identified on the
basis of ID data. FIG. 9 shows only the three types of cartridges (color
cartridges). ID=0 (not shown) indicates a monochrome cartridge, whereas
ID=1, 2, or 3 indicates a color cartridge. That is, FIG. 9 shows an
example of the classification of color cartridges. In this case, as the ID
number increases, the pigment density of at least one of the coloring
materials decreases.
Assume that in the first embodiment, the cartridge indicated by ID=1 is the
head cartridge of the pigment densities (high densities) used in a
conventional color printer. ID=2 indicates the head cartridge or ink tank
used in this embodiment and containing coloring materials having low
pigment densities except for the yellow coloring material. ID=3 indicates
the head cartridge or ink tank containing inks having lower pigment
densities, which is used in the embodiment to print a high-quality
pictorial image.
First of all, on the basis of the ID values defined in this manner, the
printer apparatus recognizes the differences in pigment density. In this
case, the differences in pigment density mean the differences in maximum
optical reflection density between the respective primary color coloring
materials, and may accompany changes in pigments themselves. In this
sense, these ID values can indicate the differences in maximum optical
reflection density or maximum saturation between the respective primary
color coloring materials. For the sake of descriptive convenience, in the
first embodiment, the ID values indicate the differences in pigment
density.
In the cartridges indicated by ID=1 and ID=2, the yellow coloring materials
have the same pigment density (2.5%). The pigment density of magenta
corresponding to ID=2 is 1/3 that of magenta corresponding to ID=1. The
pigment density of cyan corresponding to ID=2 is 1/3 that of cyan
corresponding to ID=1. The pigment density of K (Bk) corresponding to ID=2
is about 1/2 that of K (Bk) corresponding to ID=1. In the cartridges
indicated by ID=1 and ID=3, the yellow coloring materials have the same
pigment density (2.5%). The pigment density of magenta corresponding to
ID=3 is about 1/4 that of magenta corresponding to ID=1. The pigment
density of cyan corresponding to ID=3 is about 1/4 that of cyan
corresponding to ID=1. The pigment density of K (Bk) corresponding to ID=3
is about 1/4 that of K (Bk) corresponding to ID=1.
As shown in FIG. 10, in the first embodiment, when the pigment density is
set to 1/2, the optical reflection density is about 76%. When the pigment
density is set to 1/3, the optical reflection density is about 60%. When
the pigment density is set to 1/4, the optical reflection density is about
53%. When the pigment density is set to 3/4, the optical reflection
density is about 90%. This relationship between the pigment density and
the optical reflection density is almost constant regardless of the type
of color.
Referring to FIG. 9, the data in "DATA" indicates the depth of the
structure of data corresponding to each ID data and sent from the printer
driver 103 to a printer apparatus 200. This data is changed to change the
maximum ejection amount while increasing the gradation level of the print
data with changes in the pigment densities of the respective coloring
materials. This change may be accompanied by a change in the amount of
coloring material discharged from the head cartridge. In this case as
well, the data in "DATA" is basically determined on the basis of the
amount of coloring material, i.e., pigment, ejected per unit area. This
operation is also included in the scope of the present invention. Assume
that in this embodiment, the amount of ink discharged is constant. In the
embodiment, the resolution is set to 360.times.360 dip regardless of the
ID value. When ID=1, binary data is set. When ID=2, quaternary data is
set. When ID=3, quinary data is set.
Even if the resolution is increased while the gradation level of data is
fixed regardless of the ID value, almost the same effects as those in this
embodiment, in which the gradation level is increased, can be obtained.
The data in "CORRESPONDING MEDIA" indicates the types of media (printing
media) suited for a head cartridge 1 indicated by each ID value.
Various criteria for selection of corresponding media may be set. In this
case, corresponding media are discriminated on the basis of the
differences in maximum coloring material absorbing capacity. In this
embodiment, the maximum coloring material absorbing capacity of a
pictorial medium (pictorial paper) is about 500%, and the maximum coloring
material absorbing capacity of coated paper is about 400%, which is the
second largest. The maximum coloring material absorbing capacity of plain
paper is about 200%, which is the smallest.
The data in "MAXIMUM INJECTION AMOUNT" in FIG. 9 vary depending on C, M, Y,
and K coloring materials and R, G, and B coloring materials. The numerical
values in "MAXIMUM INJECTION AMOUNT" represent the maximum ejection
amounts limited in the printer driver 103 in units of pixels. That is, the
surface density of a coloring material is changed for each density to set
almost the same pigment amount at portions exhibiting the same density. A
characteristic feature of this embodiment (ID=2 and 3) is that the maximum
ejection amount of the secondary color coloring material (R, G, or B) is
less than twice that of the primary color coloring material (C, M, Y, or
K), unlike the prior art (ID=1).
As is apparent from FIG. 9, the data in "PIGMENT DENSITY" and "MAXIMUM
INJECTION AMOUNT" are changed according to the following relationship.
The pigment densities of chromatic coloring materials, i.e., cyan, magenta,
and yellow (to be referred to C, M, and Y hereinafter) coloring materials,
having almost the same hue (almost the same color) corresponding to
different ID values are compared to obtain at least one high pigment ratio
and one low pigment ratio. The maximum ejection amount is then changed to
be equal to or higher than the sum of the maximum and minimum ratios.
When, for example, the cartridge indicated by ID=1 is compared with the
cartridge indicated by ID=2, the colors of the coloring materials having
almost the same hue and exhibiting the maximum pigment density ratios are
C and M. The ratio between the M coloring materials is "3", and the ratio
between the C coloring materials is also "3" (maximum value). The Y
coloring materials exhibit the minimum value, which is "1". The sum of the
maximum and minimum is "4". In this case, therefore, the maximum ejection
amount is set to equal to or higher than 4 (=3+1) times that in the prior
art, i.e., 400%. More specifically, in the cartridge indicated by ID=2,
the maximum ejection amount of each of the primary color coloring
materials (C, M, and Y) is set to "300%", and that of each of the
secondary color coloring materials (R, G, and B) is set to "400%" with
respect to those in the cartridge indicated by ID=1.
By determining the maximum ejection amounts in this manner, an image having
almost the same optical reflection density as that of an image obtained by
using the head cartridge indicated by ID=1, which contains inks having
high pigment densities, can be obtained by using the primary color
coloring materials of C and M. In addition, since the Y coloring material
has the same pigment density as that in the cartridge indicated by ID=1,
the maximum ejection amount need not be changed from "100%". In the case
shown in FIG. 10, therefore, when an ink having a dye density of 1/3 is
discharged three times that in a dye density of 1/1(normal case) to print
an image, the amount of dye discharged becomes about three times that in
the normal case. Since water such as a dilute solution is absorbed by the
printing medium and evaporated, the resultant image has an optical
reflection density almost three times that in the normal case. As is
apparent from FIG. 10 as well, when the dye density is 2/3 or more, the
reflection density becomes "0.9" or more and almost saturated. For this
reason, there is no conspicuous difference in reflection density between
the images obtained with different dye densities.
Consider secondary colors, e.g., red, green, and blue (to be referred to as
R, G, and B hereinafter) next. The maximum ejection amounts corresponding
to these secondary colors correspond the ink absorbing capacities of media
(printing media). In the case shown in FIG. 9, the plain paper has the
smallest absorbing capacity (200%), and the coated paper has the next
smallest capacity (400%). The pictorial paper has the largest ink
absorbing capacity (500%).
Consider R first. The R coloring material is expressed by (M+Y) using ink
pigments. In this case, as described above, since the Y coloring material
has a high pigment density (high lightness), the maximum ejection amount
is 100%. In addition, the maximum ejection amount of the M coloring
material is set to 300%. Therefore, the maximum ejection amount of the R,
i.e., (M+Y), coloring material is 400%. Almost the same optical reflection
density as the R value corresponding to ID=1 can be obtained. Similarly, G
is expressed by (C+Y). Since the maximum ejection amount of the C coloring
material is set to 300%, the maximum ejection amount of the G coloring
material is set to 400%. With this setting, an image having almost the
same optical reflection density as that of an image obtained with the G
coloring material corresponding to ID=1 can be obtained. Consider B next.
Since B is expressed by (C+M), the maximum ejection amount of the B
coloring material is set to 600% (=300%+300%). In this case, however, an
increase in optical reflection density is small relative to an increase in
ink ejection amount. For this reason, in practice, the maximum ejection
amount is set to 400% (C+M=200%+200%). With this setting, the optical
reflection density of the printed image is about 90% that of an image
obtained by using the head cartridge indicated by ID=1.
Similar calculations are performed when the head cartridge indicated by
ID=3 is used. That is, according to the relationship between ID=1 and
ID=3, the maximum ejection amounts of primary color coloring materials (C
and M) are set to 400%, and the maximum ejection amounts of the secondary
color coloring materials (R, G, and B) are set to 500% or more. In this
case, almost the same optical reflection densities as those corresponding
to ID=1 can be obtained with the secondary color coloring materials except
for the B coloring material. When the maximum ejection amount of the B
coloring material is set to 500%, however, the optical reflection density
is slightly lower than that corresponding to ID=1. The maximum ejection
amount of the B coloring material may therefore be set to 600%. In any
case, when the maximum ejection amounts are changed in this manner, the
data in "CORRESPONDING MEDIA" are limited, as shown in FIG. 9. A pictorial
image can therefore be obtained by decreasing the pigment densities,
changing the maximum ejection amounts in accordance with the pigment
densities, and using the optimal "corresponding medium" for the pictorial
image.
With the above operation, the optimal effects can be obtained by changing
the maximum ejection amounts. In practice, even if the maximum ejection
amounts with respect to the medium cannot be changed to ideal amounts,
image design may be performed with respect to an output data curve
(ID=2-q) to slightly lower its level from the ideal level by clipping
(ID=2-b) data at high gradation levels (high densities) of data to be
output in response to an input or using a high-order curve.
Even if an increase in maximum ejection amount is suppressed by clipping
data in the above manner, effects equivalent to those in the ideal state
can be obtained up to a certain gradation level. In this case, the pigment
density per unit area can be kept almost constant regardless of the type
of coloring material before clipping.
FIGS. 11A and 11B explain the layouts of dots printed in the first
embodiment.
FIG. 11A shows the layout of dots on a printing medium in a case wherein
binary data is printed at 360 dpi.times.360 dpi. FIG. 11B shows the layout
of dots on a printing medium in a case wherein quaternary or quinary data
is printed at 360 dpi.times.360 dpi.
In the case shown in FIG. 11A, the ejecting ratio is set such that one dot
is printed on each pixel. This ejecting ratio is defined as 100%. In the
case shown in FIG. 11B, therefore, the ejecting ratio is 200%. Note that
when the amount of ink discharged is to be changed in each cartridge, a
value obtained when 100% is multiplied by the changed ratio may be set to
perform a print operation regardless of the type of data, i.e., binary,
quaternary, or quinary data, even if all the dots corresponding to the
respective pixels are present.
FIGS. 12A to 12C show the relationship between the data form and the layout
of dots actually printed on a printing medium by the printer apparatus 200
of the first embodiment.
FIG. 12A shows 360-dpi binary data. FIG. 12B shows 360-dpi quaternary data.
FIG. 12C shows 360-dpi quinary data. In this case, the binary data in FIG.
12A is printed according to the dot layout shown in FIG. 11A. The
respective pixel data and the printed dots exhibit a one-to-one
correspondence. Therefore, when data is "0", no dot is printed, whereas
when data is "1", one dot is printed at a corresponding pixel position
corresponding to 360 dip.times.360 dpi. In this embodiment, such a
printing method is executed when the head cartridge 1 indicated by ID=1 is
mounted in the printer apparatus to perform a print operation.
FIG. 12B shows a print operation using quaternary data which is executed
when the head cartridge 1 indicated by ID=2 is mounted in the printer
apparatus. In this case, a dot (denoted by reference numeral 700 in FIGS.
11A and 11B) is printed at an address corresponding to 360 dpi.times.360
dpi, and a sub-dot (denoted by reference numeral 701 in FIG. 11B) is also
printed at an address corresponding to 720 dpi.times.360 dpi. In this
case, data is supplied through a 2-bit signal. When data is "00", no dot
is printed. When data is "01", one dot is printed at an address
corresponding to 360 dpi.times.360 dpi. When data "10", the data is
decoded in the ink-jet printer apparatus to print one dot at an address
(700) corresponding to 360 dpi.times.360 dpi and one dot at an address
(701) corresponding to 720 dpi.times.360 dpi. This state corresponds to
200% ink ejection at 360 dpi.times.360 dip (FIG. 11A). When data is "11",
two dots printed at an address (700) corresponding to 360 dpi.times.360
dpi in an overlapping state, and one dot is printed at an address (701)
corresponding to 730 dpi.times.360 dpi, thereby realizing 300% ink
ejection relative to the ejection operation in FIG. 11A.
FIG. 12C shows the case wherein 4-bit data is output as quinary data.
However, another method may be used. The print operation in FIG. 12C
differs from that in FIG. 12B in that when quinary data is "111", two dots
are printed in an overlapping state at both an address (700) corresponding
to 360 dpi.times.360 dpi and an address (701) corresponding to 720
dpi.times.360 dpi. With this operation, when quinary data is used, a
primary color ink can be ejected at a maximum of 400%. As is apparent, the
data may be decoded to print dots, as in the case shown in FIG. 12B.
In order to execute the above printing method with the increased gradation
level, two dots must be printed in an overlapping state at each pixel
position. For this reason, a print operation must be performed by a known
multi-pass method.
According to another embodiment, a print operation may be performed with
the same number of passes or by the multi-pass method by increasing the
density of print elements in units of cartridges. Assume that a head
cartridge having print elements arranged at a 360-dpi pitch has been used,
and the gradation level is to be increased. In this case, a print
operation may be performed by using a head cartridge having print elements
arranged at a 720-dpi pitch.
FIG. 13 is a block diagram showing the arrangement of the printer apparatus
200 of the first embodiment. The same reference numerals in FIG. 13 denote
the same parts as in the above drawings.
Reference numeral 301 denotes a control unit for controlling the overall
operation of the printer apparatus. The control unit 301 includes a CPU
310 such as a microprocessor, a ROM 311 storing control programs executed
by the CPU 310 and various data, a RAM 312 which is used as a work area
when the CPU 310 executes various processes and temporarily stores various
data, and the like. The RAM 312 incorporates a reception buffer for
storing print codes received from a host computer 100 and print buffers
corresponding to Y, M, C, and B and storing print data (image data) in
correspondence with yellow, magenta, cyan, and black printheads 1Y, 1M,
1C, and 1B for printing Y, M, C, and Bk images, respectively.
Reference numeral 302 denotes a head driver for driving the yellow
printhead 1Y, the magenta printhead 1M, the cyan printhead 1C, and the
black printhead 1B in accordance with print data of the respective colors
which are output from the control unit 301; 303 and 304, motor drivers for
rotating/driving the carriage motor 6 and a conveyance motor 305,
respectively; 306, an interface (I/F) unit for controlling the interface
between the printer apparatus 200 of this embodiment and the host computer
100; and 307, an operation unit having various keys operated by the user
and a display unit such as a liquid crystal display.
FIG. 14 is a flow chart showing a print code generation processing executed
by the host computer 100 in the first embodiment. For example, this
processing is executed by the printer driver 103.
In step S1, the type of printing medium to be used in the printer apparatus
200 is designated. In step S2, the type (ID data) of the head cartridge 1
mounted in the printer apparatus 200 is determined on the basis of a
signal from the printer apparatus 200 For example, determination of the
type of cartridge, designation of the type of printing medium, and the
like are performed by setting a mode and the like of the printer apparatus
200 on the window displayed by the OS 101 of the host computer 100. In
step S3, the type of the head cartridge 1 mounted in the printer apparatus
200 is checked. If, for example, the cartridge indicated by ID=1 is
mounted, the flow advances to step S4 to binarize the image data of the
respective color components as in a known conventional method.
If it is determined in step S3 that the head cartridge 1 indicated by ID=2
is mounted, the flow advances to step S5 to binarize the Y data and
convert the print data corresponding to the remaining colors into
quaternary data. If it is determined in step S3 that the head cartridge 1
indicated by ID=3 is mounted, the flow advances to step S6 to binarize the
Y data and convert the print data corresponding to the remaining colors
into quinary data. In step S7, print codes are generated on the basis of
the print data obtained by conversion in one of steps S4, S5, and S6, and
the codes are sent to the printer apparatus 200 through the interface 306.
FIG. 15 is a flow chart showing print processing in the printer apparatus
200 of the first embodiment. The control program for executing this
processing is stored in the ROM 311.
In step S11, the print codes received from the host computer 100 and stored
in the reception buffer are read out. In step S12, the readout print codes
are decoded. The flow then advances to step S13 to convert the codes into
print data corresponding the respective colors in accordance with the
decoding result. Thereafter, the flow advances to step S14 to check on the
basis of the received data whether a print operation can be performed by
using the currently mounted head cartridge 1. If NO in step S14, the flow
advances to step S15 to give an indication of an error on the operation
unit 307 and terminate the process.
If YES in step S14, the flow advances to step S16 to check whether the head
cartridge ID data is "1". If YES in step S16, the flow advances to step
S17 to convert all the color data into binary print data and develop the
data in the print buffers. In step S18, a general 1-pass print operation
is performed.
If it is determined in step S16 that the head cartridge ID data is not "1",
the flow advances to step S19 to convert only the Y data into binary data
and convert the remaining color data into quaternary or quinary data. Note
that this processing may be uniquely determined on the basis of the print
codes or independently performed on the printer apparatus side on the
basis of the ID data of the head cartridge mounted in the printer
apparatus. Thereafter, the flow advances to step S20 to store the print
data, which have been developed into patterns of the respective colors, in
the print buffers in correspondence with the respective colors. The flow
then advances to step S21 to print the multivalued data by the multi-pass
method, as described above with reference to FIGS. 11A and 11B and 12A to
12C.
FIG. 16 is a flow chart showing print processing performed by such a
multi-pass method (step S21).
In step S31, rotation of the carriage motor 6 is started. In step S32, the
respective color print data to be printed next are read out from the print
buffers corresponding to the respective colors, and it is checked whether
the print timing at which a print operation is performed in a resolution
of 360 dpi has come. If YES in step S32, the flow advances to step S33 to
output the print data corresponding to the respective colors to the heads
1Y, 1M, 1C, and 1B through the head driver 302, thereby printing dots at
the position denoted by reference numeral 700 in FIG. 11B (when the data
is not "0" or "00"). The flow then advances to step S34 to check whether
the multivalued data excluding the Yellow print data include data of "10"
or more. If NO step S34, since only one dot is to be printed as in the
case in FIG. 12A, the flow advances to step S37.
If it is determined in step S34 that the data include data of "10" or more,
the flow advances to step S35 to check whether the timing at which the
720-dpi dot denoted by reference numeral 701 in FIG. 11B is printed has
come. If YES in step S35, the flow advances to step S36 to output the
print data to the heads 1M, 1C, and 1B of the corresponding colors and
print an image. The flow then advances to step S37 to check whether the
print processing corresponding to one scanning operation is complete. If
NO in step S37, the flow returns to step S32 to execute the above process.
If YES in step S37, the flow advances to step S38 to perform a carriage
return to return the head to the home position. The flow then advances to
step S39 to rotate/drive the carriage motor 6 again in the forward
direction. In step S40, as in step S32, it is checked whether the print
timing at which a print operation is performed in a resolution of 360 dpi
has come. If YES in step S40, the flow advances to step S41 to check
whether the print data include data of "11" or more. If YES in step S41,
the flow advances to step S42 to print the dot data at the corresponding
position. The flow then advances to step S43 to check whether the print
data include data of "1000" (the maximum quinary value). If YES in step
S43, the flow advances to step S44 to check whether the print timing
corresponding to 720 dpi has come. If YES in step S44, the flow advances
to step S45 to print one dot at the corresponding position.
If it is determined in step S46 that the print operation corresponding to
one scanning operation is complete, the flow advances to step S47 to
execute a carriage return to return the carriage unit 2 to the home
position, and drive the conveyance motor 305 so as to convey the print
paper sheet by a distance corresponding to total width (print width) of
the print elements of the head of each color. With this operation, an
image corresponding to the print width is printed by the printhead of each
color. The flow then advances to step S48 to check whether a print
operation corresponding to one page is complete. If NO in step S48, the
flow returns to step S1 to generate print data corresponding to an image
to be printed by the next scanning operation and store the data in the
print buffers of the respective colors. When the image print operation
corresponding to one page is complete in this manner, the flow advances to
step S49 to discharge the resultant print paper sheet and terminate the
process.
[Second Embodiment]
In the first embodiment described above, as shown in FIG. 17, when a print
operation is to be performed, the type of head cartridge mounted in a
printer apparatus 200 is determined, and the print mode corresponding to
the type of head cartridge is automatically set by the driver of the host
computer, thereby controlling the operation upon interlocking the color
processing performed by the driver with the processing performed by the
controller.
In contrast to this, in the second embodiment, the user is allowed to
arbitrarily set a print mode on the display screen of a host computer 100
so as to reliably select a print mode in accordance with a user's
application purpose.
The operation in FIG. 17 will be briefly described below. The host computer
100 inquires about the type of cartridge mounted in the printer apparatus
200 (step S300). With this operation, the printer apparatus 200
discriminates the type of mounted cartridge by reading the ID data of the
cartridge (step S310). The printer apparatus 200 then returns the ID data
to the host computer 100 (step S320). Upon reception of the ID data (step
S330), the host computer 100 causes the driver to perform color processing
for the image data in accordance with the color of the cartridge (step
S340). The host computer 100 transmits the resultant color signals as C,
M, Y, and K signals and a mode signal to the printer apparatus 200 (step
S350). The printer apparatus 200 receives these signals and causes the
controller to perform image development (step S370), and prints an image
(step S380).
Note that since the arrangements of the host computer and the printer
apparatus of the second embodiment are the same as those of the first
embodiment, a description thereof will be omitted.
FIG. 18 is a flow chart showing print mode setting in the second
embodiment.
When the printer apparatus 200 is powered on, and a head cartridge 1 is
mounted, the type of the head cartridge 1 is checked on the basis of the
ID data of the head cartridge as in the first embodiment (step S200). An
ID signal representing the check result in step S200 is sent to the host
computer 100 (step S210). The processing in steps S200 and S210 is
performed by the printer apparatus 200. The following processing is
performed by the host computer 100.
The type of head cartridge currently mounted in the printer apparatus 200
is registered as a condition of the printer apparatus, together with the
type of the printer apparatus 200 and the like, on the basis of the ID
signal received from the printer apparatus 200 (step S220). A print mode
is then designated by the user (step S230). The user manually sets the
print mode corresponding to his/her application purpose on the basis of
the user interface (UI) displayed on the display screen of the host
computer 100, like the one shown in FIG. 19 (step S240).
In the second embodiment, the print modes correspond to the types of head
cartridges 1, as shown in FIG. 9. The normal mode, the pictorial mode 1,
the pictorial mode 2, and the monochrome mode correspond to ID1, ID2, ID3,
and ID0, respectively.
As described in the first embodiment, each head cartridge 1 corresponds to
one of the print modes. Therefore, whether the head cartridge 1
corresponding to the set print mode is mounted is determined by checking
the type of head cartridge 1 which is registered in step S220 (step S250).
If the head cartridge 1 corresponding to the set print mode is mounted, the
host computer 100 instructs the user to set a printing medium
corresponding to the print mode. In the second embodiment, as shown in
FIG. 9, the normal mode corresponds to plain paper, coated paper, and
pictorial paper. If, therefore, the normal mode is set, the host computer
100 instructs the user, for example, in the manner shown in FIG. 20.
If the head cartridge 1 corresponding to the set print mode is not mounted,
the host computer 100 instructs the user to replace the cartridge with the
head cartridge 1 corresponding to the print mode (step S270). Assume that
the pictorial mode 1 is set even though the currently head cartridge 1
corresponds to the normal mode (ID=1). In this case, as shown in FIG. 21,
the host computer 100 instructs the user to replace the head cartridge 1
with the proper type of head cartridge (indicated by ID=2). By repeating
steps S200, S210, S220, and S250, the host computer 100 checks whether the
head cartridge 1 is replaced with the head cartridge 1 corresponding to
the print mode (step S280). When the head cartridge 1 and the printing
medium corresponding to the set print mode are set in this manner, the
driver starts to perform the color processing shown in FIG. 8 (step S290).
Thereafter, the host computer 100 performs the same processing as that in
the first embodiment described above.
As described above, according to the second embodiment, an image can be
reliably printed in the print mode corresponding to the user's application
purpose, and an erroneous image print operation caused by a print mode
setting error or the like can be prevented.
Note that if the normal or monochrome mode is set, since the type of a
printing media to be used are not limited, the processing in step S206 may
be omitted. In this case, since the number of times warning display is
performed can be decreased, a user-friendlier UI can be provided.
FIG. 22 is a flow chart showing an example of the image processing
performed by the image processing module in a printer driver 103, which
corresponds to FIG. 8. The processes common to the flow charts in FIGS. 8
and 22 are denoted by the same reference symbols, and a description
thereof will be omitted. In the processing in FIG. 22, a print mode is set
through the above UI (step S100), and image processing is performed in
accordance with the set print mode.
Note that when the host computer 100 is connected to the printer apparatus
200 through a one-way communication line, the driver of the host computer
100 sets a print mode using a predetermined head cartridge in accordance
with an instruction manually input by the user. As in the first
embodiment, the controller of the printer apparatus 200 automatically
discriminates the type of the head cartridge 1, and automatically sets a
print mode on the basis of the discriminated type of the head cartridge 1.
The controller then receives image data indicating the print mode manually
designated by the user from the driver through the one-way communication
line. If the print mode indicated by the received data coincides with the
print mode automatically set by the controller, print processing is
executed. If these modes do not coincide with each other, the occurrence
of an error is displayed on an operation unit 307 of the printer apparatus
to notify the user of the error. With this display, the user checks the
type of printhead mounted in the printer apparatus 200 and sets a print
mode again in accordance with the type of printhead. This operation can
prevent the printer apparatus from printing an image in a mismatching
print mode. The number of times of misprinting can be reduced.
According to the above description, in this embodiment, the processing in
the host computer 100 and the processing in the printer apparatus 200 are
separately performed. However, the present invention is not limited to
this. These functions may be implemented in one apparatus or unit.
In addition, a print element separation means separates achromatic color
components to express the high-lightness portions of the achromatic color
components by process black consisting of a mixture of yellow, magenta,
and cyan, and express the low-lightness portions of the achromatic color
components by black. With this operation, an achromatic color component
print can obtain gradation by means of the process black and black ink.
Since the high-lightness portions are expressed by the process black, an
image with little graininess can be obtained. That is, it suffices if the
graininess of black dots on a transition portion from the process black to
black is reduced. Even if an ink having a higher dye density than magenta
and cyan inks is used, the graininess and gradation characteristics do not
deteriorate.
In this embodiment, even if a dilute ink is used for an image with a low
gradation level, e.g., a document or bar chart image, the gradation
characteristics do not improve. When a dilute ink is used to print a
high-density image, since three ink droplets are ejected onto a printing
medium, the ink overflows depending on the type of printing medium. This
printer apparatus therefore includes a means of allowing the user to
select an ink used by the print elements in accordance with the image and
the type of printing medium to be used.
FIG. 23 shows head cartridges containing different inks to be used by the
print elements and the printer apparatus main body. FIG. 24 is a block
diagram of the printer apparatus. The same reference numerals in FIGS. 23
and 24 denote the same parts as in FIGS. 2 and 13, and a description
thereof will be omitted.
ID data which can recognized by the printer apparatus are assigned to these
head cartridges. The dye densities of the inks in the head cartridge
indicated by ID=1 are: 2.5% in the yellow ink; 3.0% in the magenta ink;
2.7% in the cyan ink; and 2.6% in the black ink. The dye densities of the
inks in the head cartridge indicated by ID=2 are: 2.5% in the yellow ink;
1.0% in the magenta ink; 0.9% in the cyan ink; and 1.3% in the black ink.
The dye densities of the inks in the head cartridge indicated by ID=3 are:
2.5% in the yellow ink; 0.8% in the magenta ink; 0.7% in the cyan ink; and
0.9% in the black ink.
In the second embodiment, with the use of the inks corresponding to ID=1,
one yellow pixel can be properly expressed in binary gradation; one
magenta pixel, in binary gradation; one cyan pixel, in binary gradation;
and one black pixel, in binary gradation. With the use of the inks
corresponding to ID=2, one yellow pixel can be properly expressed in
binary gradation; one magenta pixel, in quaternary gradation; one cyan
pixel, in quaternary gradation; and one black pixel, in binary gradation.
With the use of the inks corresponding to ID=3, one yellow pixel can be
properly expressed in binary gradation; one magenta pixel, in quinary
gradation; one cyan pixel, in quinary gradation; and one black pixel, in
ternary gradation.
With the inks corresponding to ID=1, one-pixel yellow print data is handled
as one bit; one-pixel magenta print data, as one bit; one-pixel cyan print
data, as one bit; and one-pixel black print data, as one bit. With the
inks corresponding to ID=2, one-pixel yellow print data is handled as one
bit; one-pixel magenta print data, as two bits; one-pixel cyan print data,
as two bits; and one-pixel black print data, as two bits. With the inks
corresponding to ID=3, one-pixel yellow print data is handled as one bit;
one-pixel magenta print data, as three bits; one-pixel cyan print data, as
three bits; and one-pixel black print data, as two bits.
In the printer apparatus, the configurations of the print buffers are
changed in accordance with the ID data of the head cartridge. When the
head cartridge indicated by ID=1 is mounted, all the print buffers are
made to have 1-bit configurations. When the head cartridge indicated by
ID=2 is mounted, the print buffer for yellow data is made to have a 1-bit
configuration, and the print buffers for the remaining colors are made to
have 2-bit configurations. When the head cartridge indicated by ID=3 is
mounted, the print buffer for yellow data is made to have a 1-bit
configuration, the print buffers for magenta and cyan data are made to
have 3-bit configurations, and the print buffer for black data is made to
have a 2-bit configuration.
As described above, since the user selects a head cartridge in accordance
with the image to be printed and the type of printing medium, the
gradation level of the image to be printed can be changed. In this case as
well, an increase in the capacity of each print buffer can be suppressed
by suppressing the gradation of a high-lightness yellow image.
[Third Embodiment]
The third embodiment of the present invention will be described next. In
the ink-jet printer apparatus of this embodiment, when an image with the
highest quality is to be printed, the image is formed by using the
divisional printing method described below. In this divisional printing
method, image data is generated by a thinning process using a plurality of
mask patterns (to be referred to as masks hereinafter), and the printhead
is scanned a plurality of numbers of times using the image data, thereby
printing an image.
In this divisional printing method, since a print operation is performed by
using different portions of the nozzle array of a head cartridge 1 in a
plurality of scanning operations, image irregularity based on the
directions in which inks are discharged from the head cartridge 1, the
amounts of inks discharged from the respective nozzles, and the like can
be reduced.
FIGS. 26A and 26B show examples of the above masks. For example, each of
these masks is used to thin out image data by 50% to print an image by
performing a scanning operation twice. The mask patterns shown in FIGS.
26A and 26B have complementary data configurations.
Assume that image data is thinned out by each mask data by a ratio below
50% (i.e., the number of dots to be actually printed is increased), as
shown in FIGS. 27A and 27B, and an image is printed in the same manner as
described above. In this case, as is apparent, many droplets of ink can be
ejected onto a printing medium. When an image is to be printed by using a
thin ink, a larger amount of ink must be ejected onto a printing medium
than when a thick ink is used. For this reason, the mask data in the above
divisional printing method are changed to change the amount of ink ejected
onto the printing medium depending on whether a thick or thin ink is used.
When inks having different densities are to be used in combination in
accordance with the color of an image, the masks used in the above
divisional printing method are changed for each color to control the
amount of ink ejected, thereby ejecting an ink onto a printing medium in
an amount required for each color. With this control, an image with a
predetermined density can be printed.
In the third embodiment, when an image is to be printed by using a thin
ink, a scanning operation is performed the same number of times as in a
print operation using a thick ink. In this case, as described above, the
divisional printing method is used. More specifically, the masks for
generating thinned image data are changed to increase the amount of ink
ejected onto a printing medium per scanning operation. With this
operation, a thin ink can be ejected onto the printing medium in an amount
required to form an image without changing the number of times of
scanning. In this case as well, the driving frequency of the head
cartridge 1 is set to prevent the ink from overflowing the printing
medium.
This printing method has the following merits. For example, in a print
operation using a thin ink, when the amount of ink ejected per unit time
is to be suppressed to a predetermined amount or less, the number of times
of scanning in the divisional printing method must be increased to obtain
a predetermined print density. As a result, the print time is prolonged on
a unit-time (required for one scanning operation) basis. In contrast to
this, according to the method of the third embodiment, an image can be
printed by the same number of times of scanning as in a print operation
using a thick ink, and the amount of ink ejected onto a printing medium
member per unit time can be set by setting the driving frequency of the
printhead to a predetermined driving frequency. This method can therefore
prevent an ink from overflowing the printing medium and print an image at
the maximum speed.
If a printing medium has a sufficient ink absorbing capacity, a necessary
amount of thin ink can be ejected onto the printing medium to print an
image. That is, in a print operation using a thin ink, an image can be
printed by performing a scanning operation the same number of times with
the same driving frequency of the printhead as in a print operation using
a thick ink.
In addition, in print control using a thick ink, an optimal driving
frequency is set to allow the printhead to stably discharge the ink in
consideration of a combination of the thick ink, the printhead, and the
like. Note that a thin ink contains a color developing material such as a
dye or pigment in a smaller amount than a thick ink, or the amount of an
organic material to be added to disperse such a color developing material
or delay the solidification of the ink can be reduced. In general,
therefore, a thin ink has a lower viscosity, and the time interval between
the instant at which the ink is discharged from the printhead and the
instant at which the next ink is supplied and can be discharged is
shorter. For this reason, the driving frequency of the printhead in a
print operation using a thin ink can be set to be higher than that in a
print operation using a thick ink. That is, an image can be printed at a
high speed in use of a thin ink.
Furthermore, in the third embodiment, when an image is to be printed by
using a thin ink, the printer apparatus or software (e.g., a driver 103
used by an OS 101 of a host computer 100 described above) capable of
controlling the printer apparatus identifies/detects the type of a
printing medium (print paper or the like). Alternatively, the type of
printing medium to be used for the print operation is identified upon
designation of a printing medium by the user. Thereafter, when a print
operation is performed by the divisional printing method, predetermined
masks and a predetermined driving frequency are selected in accordance
with the resultant information.
In general, printing medium greatly differs in ink absorbing capacity.
However, with the above functions corresponding to the respective printing
medium, a print operation can be performed with the ink ejection amount
corresponding to each type of printing medium at the maximum speed.
The third embodiment will be described in detail below.
FIG. 28 is a block diagram showing the arrangement of an ink-jet printer
apparatus according to the third embodiment of the present invention.
Referring to FIG. 28, reference numeral 301adenotes a control unit for
controlling the overall printer apparatus. The control unit 301a includes
a CPU 310 such as a microcomputer, a program memory 311 storing control
programs executed by the CPU 310 and various data, and a RAM 312 which is
used as a work area for temporarily storing various data when processing
is executed by the CPU 310. Reference numeral 413 denotes a mask memory
storing, for example, the plurality of mask data described above; and 414,
a frequency memory storing pieces of driving frequency information for the
printheads in correspondence with the types of inks to be used, i.e., a
thick ink and a thin ink, and the types of printing media.
A head driver 302 drives the head cartridge 1 in accordance with print data
to discharge an ink so as to print an image. This head cartridge 1 may
include printheads for discharging four different inks, as shown in FIGS.
13 and 24. Reference numeral 402 denotes a circuit for identifying the
type of ink contained in the head cartridge 1. For example, the circuit
402 has the same arrangement as that shown in FIG. 5.
Reference numeral 407 denotes a paper sensor for identifying the type of a
printing medium set in the printer apparatus. Instead of using the paper
sensor 407, an operation unit 307 may be used to designate the type of ink
contained in the head cartridge 1 or the type of a printing medium (paper)
set in the printer apparatus. Reference numeral 409 denotes a detection
unit including a temperature sensor, a humidity sensor, and the like which
are used to detect information about the environment in which the printer
apparatus is placed.
FIG. 29 is a flow chart showing print processing in the ink-jet printer
apparatus of the third embodiment. The control program for executing this
processing is stored in the program memory 311. The processing is started
when, for example, the printer apparatus receives print data corresponding
to one scanning operation or one page from the host computer, and is ready
for a print operation which is performed by scanning the head cartridge 1
once. Assume that the processing is started when one-page print data is
received.
In step S131, the control unit acquires information indicating that the ink
in the head cartridge 1 is a thick or thin ink. As described with
reference to FIGS. 5 and 6, in this step, the control unit may acquire
information indicating connection of specific lines in the circuit 402, or
may receive designation information input from the operation unit 307. The
flow then advances to step S132 to acquire information about the material
of the printing medium (print member) set in the printer apparatus. In
this step, the control unit may acquire information by using the paper
sensor 407 or acquire designation information input from the operation
unit 307.
The flow advances to step S133 to identify the type of ink in the head
cartridge 1 on the basis of the information acquired in step S132. If it
is determined that the ink is a thick ink, the flow advances to step S134
to select thick ink mask data from the mask memory 413, and select the
driving frequency information for the head cartridge 1 which is suited for
a thick ink from the frequency memory 414. The flow then advances to step
S135 to perform a print operation corresponding to one page by the
divisional printing method. The processing in step S135 will be described
later with reference to the flow chart of FIG. 30.
If it is determined in step S133 that a thin ink is contained in the head
cartridge 1, the flow advances to step S136 to determine the type of set
printing medium on the basis of the printing medium information acquired
in step S132. The type of printing medium (e.g., 1: plain paper, 2:
ink-jet print paper, 3: resin film) is determined in step S136, and the
flow advances to one of steps S137 to S139 in accordance with the
determined type to select mask data and a driving frequency which
correspond to the determined type. The flow then advances to step S135 to
perform a print operation by the divisional printing method.
FIG. 30 is a flow chart showing the print processing in step S135 in the
flow chart of FIG. 29. Note that this flow chart corresponds to the
processing of print data of one color of print data of a plurality of
colors.
At the start of this processing, a carriage motor 6 starts to rotate. In
step S51, the driving frequency of the carriage motor 6 is determined in
accordance with the driving frequency selected in one of steps S134, S137,
S138, and S139, and the carriage motor 6 is rotated/driven at the
determined driving frequency. With this operation, the carriage unit 2 is
conveyed/driven at a speed corresponding to the driving frequency. In step
S52, 1-column print data is masked by one of the mask data, e.g., the mask
data shown in FIG. 27A, which is selected in one of steps S134, S137,
S138, and S139. When the head cartridge 1 reaches the print position, and
the print timing has come, the flow advances from step S53 to step S54 to
output the print data to the head driver 302 so as to drive the head
cartridge 1. In step S55, it is checked whether the print operation
corresponding to one scanning operation is complete. If NO in step S55,
the flow returns to step S51 to repeatedly execute the above processing.
If YES in step S55, the flow advances to step S56 to return the head
cartridge 1 to the print start position. The carriage unit 2 is
conveyed/driven again at a speed corresponding to the driving frequency.
In this case, the print data is masked by using one of the above mask
data, e.g., the mask data in FIG. 27B. Thereafter, in steps S59 to S61, a
print operation corresponding to one scanning operation is performed in
the same manner as in steps S53 to S55 described above. When the print
operation corresponding to one scanning operation is complete, the flow
advances to step S62 to perform a carriage return and feed the paper sheet
by a print width corresponding to one scanning operation. The flow then
advances to step S63. In step S63, it is checked whether print processing
corresponding to one page is complete. If NO in step S63, the flow returns
to step S51 to execute the above processing. If YES in step S63, the flow
advances to step S64 to discharge the printed printing medium.
As described above, according to the third embodiment, a print operation
using a thin ink can also be performed at a high speed by controlling the
amount of ink ejected in accordance with the type of ink and the type of
printing medium which are used for the print operation.
[Fourth Embodiment]
The third embodiment described above includes the means of identifying the
head cartridge 1 having an ink tank containing a relatively thick ink
(which is mounted when a print operation using a thick ink is to be
performed) or the head cartridge 1 having an ink tank containing at least
a thin ink of one color (which is mounted when a print operation using a
thin ink is to be performed), and the means of identifying the type of
printing medium used for a print operation. In this arrangement, when a
print operation is to be performed by the divisional printing method in
the above manner, the operation is performed in either the mode of
printing an image using a thin ink by performing a scanning operation the
same number of times as in a print operation using a thick ink, and the
mode of printing an image by performing a scanning operation a larger
number of times. When a printing medium with a high ink absorbing rate is
to be used, an image can be printed upon increasing the amount of ink
discharged per unit time and decreasing the number of times of scanning.
When a printing medium with a low ink absorbing rate is to be used, an
image can be printed upon decreasing the amount of ink discharged per unit
time and increasing the number of times of scanning.
That is, in the third embodiment, an image is printed by performing a
scanning operation the same number of times regardless of the type of ink
used, i.e., whether a thin or thick ink is used. However, printing medium
varies in ink absorbing capacity. If, therefore, a print operation is
performed upon decreasing the number of times of scanning (increasing the
amount of ink discharged per unit time), an ink may overflow a printing
medium even though the driving frequency of the printhead is decreased to
a certain extent. In the fourth embodiment, therefore, if the use of a
printing medium with such a low permeability is detected, the amount of
ink discharged per unit time is decreased, and the number of times of
scanning for printing an image is increased.
With this control, more types of printing medium can be used than in the
third embodiment described above. In addition, even in a print operation
using a thin ink, no overflow of the ink occurs, and the print operation
can be performed at the maximum speed.
The arrangement of the ink-jet printer apparatus of the fourth embodiment
is almost the same as that of the embodiment described above, but differs
therefrom in that a control unit 301a includes a scanning count memory 415
(FIG. 28) storing the number of times of scanning.
FIG. 31 is a flow chart showing the processing performed by the ink-jet
printer apparatus of the fourth embodiment. The control program for
executing this processing is stored in a program memory 311.
The same reference symbols in FIG. 31 denote the same steps in FIG. 29 in
the third embodiment described above, and a description thereof will be
omitted.
If the head cartridge 1 contains a thick ink, the flow advances to step
S141 to select thick ink mask data from a mask data storage unit 413,
select driving frequency information suited for the thick ink from a
frequency memory 414, and obtain the number (A) of times of scanning which
corresponds to the thick ink from a scanning count memory 415. The flow
then advances to step S1351 to perform a print operation corresponding to
one page by the divisional printing method. The processing in step S135'
is the same as in the flow chart of FIG. 30 except for the following
point. After it is determined in step S61 that a print operation
corresponding to one scanning operation is complete, it is checked whether
a scanning operation is performed the number of times of scanning which is
acquired in step S141. If a given scanning operation is not complete, the
flow returns to step S51 to start a print operation corresponding to the
scanning operation.
If it is determined in step S133 that a thin ink is contained in the head
cartridge 1, the flow advances to step S136 to check the type of printing
medium mounted on the basis of the printing medium information acquired in
step S132. In this step, the type of printing medium (e.g., 1: plain
paper, 2: ink-jet print paper, 3: resin film) is determined, the flow then
advances to one of steps S142 to S144. in accordance with the determined
type to select mask data, a driving frequency, and the number of times of
scanning. In this case, if the printing medium is determined as printing
medium 1 or 2, the number of times of scanning is "A", which is the same
as in the above print operation using the thick ink. If the printing
medium is determined as printing medium 3, the number of times of scanning
is set to "B" (A<B), which is different from the number of times of
scanning in the print operation using the thick ink.
In the fourth embodiment, when a printing medium with a low ink absorbing
rate is used, an image can be printed upon decreasing the amount of ink
discharge per unit time, and increasing the number of times of scanning.
However, the user may designate an arbitrary number of times of scanning
through an operation unit 307. In this case, the printer apparatus of the
fourth embodiment or a program such as printer driver 103 may have a
function of warning against the possibility of the overflow of an ink on a
printing medium.
[Fifth Embodiment]
The fifth embodiment includes a means for identifying a head cartridge
having an ink tank containing a relatively thick ink (which is mounted
when a print operation using a thick ink is to be performed) or a head
cartridge having an ink tank containing at least a thin ink of one color
(which is mounted when a print operation using a thin ink is to be
performed), and the means of identifying the type of printing medium used
for a print operation. Assume that a print operation using a thin ink is
to be performed by using a printing medium having the highest ink
absorbing rate or a large ink absorbing capacity. In this case, mask data
is selected such that the amount of ink ejected per unit time is maximized
within the range in which the ink does not overflow the printing medium,
and the driving frequency of the head cartridge 1 is set in accordance
with the selected amount.
Since the arrangement of the ink-jet printer apparatus of the fifth
embodiment is almost the same as that of the embodiment described above, a
description thereof will be omitted.
FIG. 32 is a flow chart showing processing performed by the ink-jet printer
apparatus of the fifth embodiment. The control program for executing this
processing is stored in a program memory 311.
The same reference symbols in FIG. 32 denote the same steps as in FIG. 29,
and a description thereof will be omitted.
If it is determined in step S133 that the head cartridge 1 contains a thick
ink, the flow advances to step S151 to select thick ink mask data from a
mask data storage unit 413, and driving frequency information "A" suited
for the thick ink from a frequency memory 414. The flow then advances to
step S135' to perform a print operation corresponding to one page by the
divisional printing method. The processing in step S135' is the same as
that in the flow chart of FIG. 30.
If it is determined in step S133 that the head cartridge 1 contains a thin
ink, the flow advances to step S136 to check the type of printing medium
mounted on the basis of the printing medium information acquired in step
S132. In this step, the type of printing medium (e.g., 1: plain paper, 2:
ink-jet print paper, 3: resin film) is determined. The flow then advances
to one of steps S152 to S154 in accordance with the determined type to
select corresponding mask data and set the driving frequency to "B" (A>B).
The flow advances to step S135' to perform a print operation by the
divisional printing method. In this case, the driving frequency of the
head cartridge 1 in a print operation using a thick ink differs from that
in a print operation using a thin ink.
[Sixth Embodiment]
The sixth embodiment includes a means of identifying a head cartridge
having an ink tank containing a relatively thick ink (which is mounted
when a print operation using a thick ink is to be performed) or a head
cartridge having an ink tank containing at least a thin ink of one color
(which is mounted when a print operation using a thin ink is to be
performed), and the means of identifying the type of printing medium used
for a print operation. When a print operation using a thin ink is to be
performed, the start of a print/scanning operation is delayed such that
after a scanning operation is finished, the next print operation is
started after an elapse of a predetermined period of time corresponding to
the type of printing medium.
In performing a scanning operation, if an ink ejected in the previous
scanning operation has not sufficiently permeated through a printing
medium and is left near its surface, the ink tends to overflow to cause a
deterioration in image quality such as a blur. In the sixth embodiment,
therefore, when a print operation using a thin ink is to be performed, and
a printing medium having a low ink absorbing rate is used, a scanning
operation is performed a predetermined period of time after the previous
scanning operation has completed, although such a standby operation is not
performed in a print operation using a thick ink.
With this operation, the printer apparatus can perform a scanning operation
for a print operation while avoiding a state in which an ink tends to
overflow so as to cause a disadvantage in permeation of the ink. The
printer apparatus can therefore perform a print operation at the maximum
speed in accordance with the printing medium to be used while preventing a
deterioration in image quality due to an ink overflow.
In the third to sixth embodiments, when an image is to be printed by using
a thin ink, print control may be changed, on the basis of the information
from the detection unit 409 described above, in accordance with the
environment and conditions (e.g., changes in the amount of ink discharged
from the head cartridge 1 with a rise in temperature in the process of the
printing operation of the head cartridge 1) in which the printer apparatus
is installed. Such a change in print control is also effective in
performing a high-speed print operation with high image quality.
The ink absorbing capacity of a printing medium greatly changes depending
on the environment. The ink discharging characteristics of the head
cartridge 1 also change with changes in temperatures. In general, the
volume of an ink droplet discharged from the head cartridge 1 increases
with a rise in temperature, while the ink absorbing rate of the printing
medium decreases with an increase in humidity. For this reason, the
printer apparatus can perform a print operation at the maximum speed
without causing any ink overflow in any conditions by changing print
control in accordance with the environment and conditions in which the
printer apparatus is installed.
In the third to sixth embodiments described above, the printer apparatus is
controlled on the basis of both information indicating whether the head
cartridge 1 having an ink tank containing a relatively thick ink is
mounted (when a print operation using a thick ink is to be performed) or
the head cartridge 1 having an ink tank containing at least a thin ink of
one color is mounted (when a print operation using a thin ink is to be
performed), and information indicating the type of printing medium used
for a print operation.
Assume that only one type of printing medium is used for a print operation
using a thin ink, or the ink absorbing characteristics of printing media
used for a print operation using a thin ink do not greatly vary. In this
case, the amount of ink discharged per unit time and the amount of ink
discharged per unit area may be controlled on the basis of only
information indicating whether the head cartridge 1 having an ink tank
containing a relatively thick ink is mounted (when a print operation using
a thick ink is to be performed) or the head cartridge 1 having an ink tank
containing at least a thin ink of one color is mounted (when a print
operation using a thin ink is to be performed). A print operation can
therefore be performed with simpler control.
In the above embodiments, the head cartridge 1 with an ink tank includes a
means 402 for identifying the type of ink. However, the present invention
is not limited to this. Other techniques may be used as long as the
printer apparatus main body can discriminate whether the ink in the head
cartridge 1 is a thick or thin ink. For example, light from a light source
may be irradiated on a transparent ink tank. The type of ink in the head
cartridge 1 may be detected on the basis of the intensity of transmitted,
reflected, or scattered light. Alternatively, the user may designate the
type of ink through a switch or the like of the printer apparatus or
software (e.g., a driver used by the OS of the computer) capable of
controlling the printer apparatus.
In addition, this embodiment can be effectively applied to a printer
apparatus and method which print an image by using a thick ink and print
an image by using an ink containing at least a thin ink of one color.
Assume that inks having different densities are to be used in combination
in accordance with a print color. This print operation can be effectively
performed by a method of controlling the amount of ink ejected by using
different masks for the respective colors in the divisional printing
method. In this case, a driving frequency and a standby condition for a
print operation are set on the basis of the maximum amount of ink ejected,
thereby preventing an ink overflow and an accompanying deterioration in
image quality.
In the flow chart of FIG. 30 described above, every time a print operation
corresponding to one scanning operation is complete, the carriage unit 2
is returned to the print start position. However, the present invention is
not limited to this. A print operation may be performed by a reciprocal
scanning operation.
The above embodiments use the system, among various ink-jet recording
systems, which has a means (e.g., an electrothermal converter or laser
light) for generating heat energy as energy used to discharge an ink, and
changes the state of an ink by using the heat energy. With this system, a
high-density, high-resolution print operation can be realized.
As for the typical structure and principle, it is preferable that the basic
structure disclosed in, for example, U.S. Pat. Nos. 4,723,129 or 4,740,796
is employed. The aforesaid method can be adapted to both a so-called
on-demand type apparatus and a continuous type apparatus. In particular, a
satisfactory effect can be obtained when the on-demand type apparatus is
employed because of the structure arranged in such a manner that one or
more drive signals, which rapidly raise the temperature of an
electrothermal converter disposed to face a sheet or a channel which holds
the fluid (ink) to a level higher than levels at which film boiling takes
place are applied to the electrothermal converter in accordance with print
information so as to generate heat energy in the electrothermal converter
and to cause the heat effecting surface of the printhead to take place
film boiling so that bubbles can be formed in the fluid (ink) to
correspond to the one or more drive signals. The enlargement/contraction
of the bubble will cause the fluid (ink) to be discharged through an
orifice so that one or more droplets are formed. If a pulse shape drive
signal is employed, the bubble can be enlarged/contracted immediately and
properly, causing a further preferred effect to be obtained because the
fluid (ink) can be discharged while revealing excellent responsibility.
It is preferable that a pulse drive signal disclosed in U.S. Pat. No.
4,463,359 or 4,345,262 is employed. If conditions disclosed in U.S. Pat.
No. 4,313,124 which is an invention relating to the temperature rising
ratio at the heat effecting surface are employed, a satisfactory print
result can be obtained.
As an alternative to the structure (linear channel or perpendicular
channel) of the printhead disclosed in each of the aforesaid inventions
and having an arrangement that discharge ports, channels and
electrothermal converters are combined, a structure having an arrangement
that the heat effecting surface is disposed in a bent region and disclosed
in U.S. Pat. Nos. 4,558,333 or 4,459,600 may be employed. In addition, the
following structures may be employed: a structure having an arrangement
that a common slit is formed to serve as a discharge section of a
plurality of electrothermal converters and disclosed in Japanese Patent
Laid-Open No. 59-123670; and a structure disclosed in Japanese Patent
Laid-Open No. 59-138461 in which an opening for absorbing pressure waves
of heat energy is disposed to correspond to the discharge section.
In addition, the invention is effective for a printhead of the freely
exchangeable chip type which enables electrical connection to the printer
apparatus main body or supply of ink from the main body by being mounted
onto the printer apparatus main body, or for the case by use of a
printhead of the cartridge type provided integrally on the printhead
itself.
It is preferable that the printer apparatus of each embodiment described
above additionally employ a printhead restoring means and an auxiliary
means, because the print operation can be further stabilized. More
specifically, it is preferable to employ a printhead capping means, a
cleaning means, a pressurizing or suction means, an electrothermal
converter, an another heating element or a pre-heating means constituted
by combining them, and a pre-discharging mode of performing a discharging
operation independently of a print operation.
Furthermore, the printer apparatus may have a multiple ink-jet printhead
structure having at least one of the following modes: a mode of printing a
multicolor image of colors having different hues, and a mode of printing a
full-color image by mixing colors, as well as a print mode of printing an
image of a main color such as black. This printhead structure may be
obtained by integrating printheads or combining a plurality of printheads.
In the embodiments, color property (including black) indicate the color
developing intensity of an ink itself or the color developing intensity of
an ink printed on a printing medium. With regard to an achromatic color,
the color property indicates the lightness of the color. In this sense,
with regard to inks containing the same dye or pigment, the color property
indicates the dye density of each ink. When inks printed on printing media
are compared with each other, the color property indicates the optical
reflection density of each ink or the maximum saturation of each ink with
almost the same hue. An ink having excellent color developing
characteristics is regarded as an ink having excellent color property.
Although a fluid ink is employed in the aforesaid embodiment of the present
invention, an ink which is solidified at the room temperature or lower as
well as softened at the room temperature, an ink in the form of a fluid at
the room temperature, or an ink which is formed into a fluid when the
print signal is supplied may be employed because the aforesaid ink-jet
method is ordinarily arranged in such a manner that the temperature of ink
is controlled in a range from 30.degree. C. or higher to 70.degree. C. or
lower so as to make the viscosity of the ink to be included in a stable
discharge range.
Furthermore, an ink which is solidified when it is caused to stand, and
liquified when heat energy is supplied in accordance with a print signal
can be adapted to the present invention to positively prevent a
temperature rise caused by heat energy by utilizing the temperature rise
as energy of state transition from the solid state to the liquid state or
to prevent ink evaporation. In any .case, an ink which is liquified when
heat energy is supplied in accordance with a print signal so as to be
discharged in the form of fluid ink, or an ink which is liquified only
after heat energy is supplied, e.g., an ink which starts to solidify when
it reaches a printing medium, can be adapted to the present invention. In
the aforesaid case, the ink may be of a type which is held as fluid or
solid material in a recess of a porous sheet or a through hole at a
position to face the electrothermal converter as disclosed in Japanese
Patent Laid-Open No. 54-56847 or Japanese Patent Laid-Open No. 60-71260.
It is the most preferred way for the ink to be adapted to the aforesaid
film boiling method.
Moreover, the printer apparatus of the present invention may take various
forms. For example, the printer apparatus may be incorporated as an image
output terminal in an information processing apparatus such as a computer,
or may be separately used as such a terminal. Alternatively, the printer
apparatus may be combined with a reader or the like to serve as a copying
machine.
The present invention can be applied to a system constituted by a plurality
of devices or an apparatus constituted by a single device. As is apparent,
the present invention is also applied to a case wherein the same effects
as described above are achieved by supplying programs to a system or
apparatus. In this case, a storage medium storing the programs according
to the present invention becomes a constituent element of the present
invention. The system or apparatus operates in a predetermined manner when
the programs are loaded from the storage medium into the system or
apparatus.
According to the above embodiments, multivalued image data is divided into
data corresponding to the respective colors, and binarization or
multivalued processing of the data is performed in accordance with the
respective colors. The present invention is not limited to this. For
example, the printer apparatus main body may have such a function. In
addition, the host computer may develop image data into print data and
transmit it to the printer apparatus instead of outputting print codes to
the printer apparatus.
In the above embodiments, the type of ink in a printhead may be identified
by identifying the type of head cartridge integrally constituted by a
printhead and a cartridge or the type of ink tank mounted in a printhead.
As described above, according to the embodiments described above, the
printer apparatus includes the means for checking whether the printer
apparatus is ready for a print operation using a thin ink. With this
means, the printer apparatus can eject an ink onto a printing medium in an
amount required for each color by changing the amount of ink ejected onto
the printing medium on the basis of the information from the means,
thereby forming an image with a necessary density.
In addition, by changing the maximum amount of ink ejected onto a printing
medium per unit time or the amount of ink ejected onto a printing medium
per unit time on the basis of information about the printing medium,
images having required densities can be printed at the maximum speed by
using many types of printing media while preventing an ink overflow and an
accompanying deterioration in image quality.
Furthermore, by changing the maximum amount of ink ejected onto a printing
medium per unit time or the amount of ink ejected onto a printing medium
per unit time on the basis of at least environmental temperature
information, images having required densities can be printed at the
maximum speed by using many types of printing media under various
environmental conditions while preventing an ink overflow and an
accompanying deterioration in image quality.
According to the embodiments, in the printer apparatus, inks having
different pigment densities are exchanged to perform a print operation by
exchanging head cartridges or ink tanks. In addition, the amount of ink
ejected or the maximum amount of ink ejected in a print operation is
changed in accordance with a combination of the pigment densities of inks
in a cartridge with changes in the pigment densities of inks upon exchange
of cartridges, thereby determining the maximum amount of coloring material
discharged onto a printing medium. With this operation, a print operation
can be performed in accordance with the type of printing medium used for
the print operation.
In the embodiments, when a print operation is to be performed by using
coloring materials having low pigment densities, each color is separated
into primary and secondary color components for each pixel, and the
maximum amount of coloring material ejected is determined for each
nth-order color component in accordance with the type of printing medium
used instead of simply increasing the maximum amount of ink having a low
pigment density in accordance with a color pigment ratio.
With this function, even if coloring materials having low pigment densities
are used, both images of primary and secondary colors can be obtained as
print images having almost the same optical reflection densities as those
of images printed by using coloring materials having high pigment
densities. The present invention is basically characterized in that the
amount of each pigment on a printing medium per unit area can be changed
by replacing a cartridge or ink tank even if coloring materials having
different pigments are used. More specifically, by making the pigment
densities almost equal to each other, the maximum densities can be made
almost equal to each other while the graininess is reduced.
According to the embodiments, the amount of ink ejected onto a printing
medium is decreased to reduce the load on the printing medium, and at the
same time the running cost can be suppressed. Since the amount of ink
ejected is changed in accordance with the pigment density of an ink to be
used, and the amount of ink ejected can be finely controlled for each
color, the present invention can be effectively applied to especially a
general ink-jet printer apparatus for printing an image on a printing
medium whose ink ejection amount limit is low.
The present invention is not limited to the above embodiments and various
changes and modifications can be made within the spirit and scope of the
present invention. Therefore, to apprise the public of the scope of the
present invention, the following claims are made.
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